ADS8584S: Current Measurement using ADS8584S-Signal chain Clarifications required

Hari T O0

Part Number: ADS8584S

Hi ,

Please find the attached block diagram. I am planning to use ADS8584S for measuring current consumed by our DSP at its different operating modes. Current varies from 10uA to 100mA.Need some clarifications regarding the signal chain as shown in the block diagram. Please see my questions below

Can I directly connect the Shunt to ADC Input as shown in figure 2? Do I need an anti-aliasing filter as shown in figure 1.? My Intention is to measure DC current.
Can I remove that 4.3K resistor 5.6nf capacitor?
May I know do I need to connect the AIN_n to other end of the shunt.
For my measurement which one will be better connecting AIN_n to the ground or to other END of shunt?
This ADC contains a PGA so no amplifier is required after Shunt; correct me if I am wrong

Regards

Hari

over 5 years ago

0 Cynthia over 5 years ago

TI__Mastermind 24940 points

Hello,

You should not connect the shunt directly to the ADC input, you should use a current sensing amplifier to measure the current and drive the ADC input. The following document might be helpful, High Current Battery Monitor Circuit even though it is not an exact application match, the concepts should be helpful. Although this device does have an integrated PGA, this does not mean that for this application a driving amplifier is not needed. The ADC measures voltages, not current, thus a current sensing amplifier is needed.

Regards

Cynthia

0 Hari T O0 over 5 years ago in reply to Cynthia

Genius 3820 points

Hi Cynthia,

Thank you very much.Do I need to put anti-aliasing filter after current sense amplifier.

Regards
Hari

0 Cynthia over 5 years ago in reply to Hari T O0

TI__Mastermind 24940 points

You should not need to, but if you see the need for it in your design as you move foward then it will not hurt.

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ADS8584S: Current Measurement using ADS8584S-Signal chain Clarifications required